Aircraft speed indicator



A ril4, 1939. c. J. CRANE ET A 2,152,635

AIRCRAFT SPEED INDICATOR- Filed May 26; 1936 s Sheets-Sheet 1 Carl JCrane fina e/P 6. Nara/7r.

INVENTOR 8.

BY 2 Z Q 7 4 ATTOjETS I 3 shets sh'eet 2 lllHll m w d w T A v N r T m 3c.;J. CRANE ET AL I AIRCRAFT SPEED INDICATOR" 'Fi led May 26, 193 6'April 4,1939.

April 1939. c. J; CRANE ET AL ,15

' AIRCRAFT SPEED INDICATOR a I Filed M21926. 193s '13 She efiS- -She'ts- 1 Carl J Crane Aka/aw 6. Aqua/r7 YINVENTORSQ ATTOR v.5

Patented Apr. 4, 1939 UNITED STATES PATENT OFFICE AIRCRAFT SPEEDINDICATOR Carl J. Crane, Fair-field, and Francis G. Nesbitt, Dayton,Ohio Application May 26, 1936, Serial No. 81,870

27 Claims.

The invention described herein may be manufactured and used by or forthe Government for governmental purposes, without the payment to me ofany royalty thereon.

The present invention relates to aircraft instruments and moreparticularly to a combined horizontal air speed and vertical air speed(rate of climb) indicator and to means for adjusting the indicator for apredetermined condition of flight of an aircraft.

One of the objects of the invention is to provide a novel and compactaircraft speed indicator which indicates the longitudinal or horizontalspeed of an aircraft obtained by measuring the differential of the Pitotor impact pressure and the static pressure produced by a -Pitotstatictube, and which also indicates the vertical speed or rate of climb ofthe aircraft obtained by measuring the rate of change of the 20 samestatic pressure, the latter pressure being the altitude or barometricpressure.

Another object of the invention is to provide a novel combination ofelements for indicating both components, horizontal and vertical, of thespeed of-an aircraft on one instrument of a standard size whereby twoinstruments usually provided for this purpose are replaced by a singleinstrument, thus greatly facilitating instrument flying.

Another object is to provide, in an instrument of the class described,novel means for adjusting the dial and pointer means of the horizontalor air speed indicating portion of the instrument so that for anydesired normal cruising speed the pointer and the number on the scalerepresenting the cruising speed are brought to a horizontal positionwith the pointer pointing to the left as viewed from the front of theinstrument shown in the present embodiment whereby said pointer movesupward when the air speed decreases below the cruising speed, as inclimbing, and moves downward when the air speed increases, as in diving.

Another object of the invention is to provide a novel instrument of theabove type in which the air speed pointer and the vertical speed or rateof climb pointer are arranged in vertical planes spaced one behind theother and concentrically mounted for rotation about a common axis and inwhich the zero of the vertical speed or rate of climb dial or scale andthe pointer thereof are normally horizontal with the pointer pointing tothe right when the aircraft is in level flight and moving upward ordownward when the aircraft is climbing or diving, and novel means foradjusting the dial and pointer of the air speed indicating portion ofthe instrument so that for, any desired cruising speed the pointer andthe number on the scale representing the cruising speed are brought to ahorizontal position with the pointer pointing toward the left as viewedfrom the front of the instrument whereby said pointer moves upward whenthe air speed decreases below the cruising speed, as in climbing, andmoves downward when the air speed increases, as in diving, and wherebythe two pointers form, in effect, a single hinged indicator, the arms ofthe hinged indicator being pivoted at the center of the face of theinstrument and forming an unbroken horizontal line across the face ofthe instrument when the aircraft on which the instrument is mounted isin level flight and flying at the desired cruising speed for which theinstrument was set, but when the aircraft starts climbing the hingedindicator will form an upright V and when the aircraft starts diving theindicator will form an inverted V.

Another object of the invention is to provide in an air speed indicator,whether combined with a vertical speed indicator or not, novel means foradjusting the dial and pointer to bring the pointer to a horizontalposition for a desired cruising speed without moving the diaphragm whichactuates the pointer, whereby leaks are eliminated in the instrumentwhich must be air-tight, thereby greatly increasing the dependability ofthe instrument.

Another object of the invention is to provide a novel indicatinginstrument having a pair of concentrically pivoted pointers forrespectively indicating two factors contributing to the maintenance of adesired condition, and means whereby said pointers may be set so thatthey form a straight line diametrically across the face of theinstrument for a desired reading of said p'ointers when the desiredcondition is maintained.

Another object is to provide in an air speed indicator having a dial, apointer, a diaphragm and mechanism for operating the pointer uponexpansion and contraction of the diaphragm, novel means including a knoband planetary gear ing actuated thereby for rotating said dial andpointer simultaneously and synchronously to bring the pointer to ahorizontal position for a desired cruising speed indicated on the dialby said pointer in its horizontal position, without rotating or in anyway moving the diaphragm which is rigidly mounted in the instrumentcasing.

Still another object of the invention is to provide, broadly, in anyindicating instrument having a dial, a pointer and means responsive tochanges in conditions or operations for operating the pointer, novelmeans for rotating the dial and pointer simultaneously and synchronouslyto bring the pointer to a desired position for a desired condition oroperation indicated on the dial by the pointer in said desired position,without rotating or in any way moving the condition responsive means.

A further object is to provide, in a novel combined air speed and rateof climb indicator having a dial and pointer for indicating air speedand a second dial and pointer concentric with the first dial and pointerfor indicating rate of climb, single means for alternately adjusting therate of climb pointer to zero and rotating the air speed dial andpointer to bring the latter to a horizontal position for a desiredcruising speed.

A still further object of the invention is to provide in an instrumentof the class described, remote control means for setting the instrumentfor a desired cruising speed from a remote point and for indicating thesetting at the remote point whereby, when an aircraft is manned by apilot and a navigator or bomber in separate cockpits or compartments,the navigator or bomber may, from his compartment or cockpit, set theinstrument which is located on the pilots instrument panel to direct thepilot to maintain the cruising speed for which the navigator or bomberhas set the instrument.

The foregoing and other objects and advantages of the invention appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawings wherein oneembodiment of the invention is illustrated. It is to be expresslyunderstood, however, that the drawings are for the purpose ofillustration only and are not to be construed as defining the limits ofthe invention, reference being had for this purpose to the appendedclaims.

The invention consists substantially in the construction, combination,location and relative arrangement of parts for obtaining the resultsdesired in accordance with the foregoing objects, as will be more fullyhereinafter set forth in the specification, as shown in the drawings byway of example, and as finally pointed out in the claims.

In the drawings wherein like reference characters refer to like parts inthe related views:

Fig. 1 is a front elevation of one form of instrument embodying thepresent invention;

Fig. 2 is a view looking from the bottom of Fig. 1 and showing theinstrument connected to a remote controller in accordance with theinvention;

Fig. 3 is a bottom view, partly in section, taken on line 3-3 of Fig. 1,showing the mannerinwhich the remote controller, when used, isconnectedto the setting mechanism of the instrument;

Fig. 4 is a longitudinal vertical section taken on line 4-4 of Fig. 1;

Fig. 5 is a longitudinal horizontal section taken on line 5-5 of Fig. 1;

Fig. 6 is a transverse section taken on line 6--6 of Fig. 4;

Fig. 7 is another transverse section taken on line 1-1 of Fig. 4; and

Fig. 8 is still another transverse section taken on line 8-8 of Fig. 4.

As indicated by the hereinbefore statedobjects the invention embodies,among other things, two adjustments in an instrument of the classdescribed by means of a. single adjusting knob.

One adjustment is for setting the vertical speed or rate of climbpointer to zero position, which is horizontal, in the event the pointerdoes not indicate zero correctly. The other adjustment is for settingthe horizontal speed pointer to a horizontal position for any desirednormal cruising speed so that said pointer moves upward when the airspeed decreases below the cruising speed and moves downward when the airspeed increases below said cruising speed.

Heretofore, a structure has been provided for setting indicatinginstruments and more particularly aircraft instruments to bring theirpointers to a horizontal position for a given condition of flight byrotating the complete instrument mechanism in its casing, as disclosedfor example in Reissue Patent No. 19,709 to J. D. Peace, Jr., datedSeptember 17, 1935 (original Patent No. 1,812,549, dated June 30, 1931).Such a structure has been satisfactory and its use has been widelyadopted but in certain types of instruments it was found disadvantageousto rotate the entire mechanism for the reason that the sensitive elementof the instrument would change its operating characteristics somewhatwhen rotated to difierent positions. Accordingly, there is provided bythe present invention a novel mechanism for the purpose mentionedwhereby only the dial and pointer of the instrument are rotatedsimultaneously and synchronously without rotating the sensitive elementthereof, this being accomplished, in the embodiment illustrated anddescribed herein, by means of a planetary gear train actuated by a knobfrom the front of the instrument.

Referring to the drawings and more particularly to Figs. 4 to 8,inclusive, the instrument embodying the present invention comprises, inthe form shown, a cup-shaped instrument casing 9 of some suitablelightweight material such as Bakelite, for example. The casing isprovided with the usual lugs or ears III- (Figs. 1 and 8) for mountingthe instrument on an instrument panel (not shown).

The instrument mechanism assembly is constructed for ready insertion andremoval as a unit into and out of the casing and comprises a frameconstituted by three substantially parallel plate members II, I2 and I3spaced apart and secured together by means of a plurality of standardsor spacing rods I4, I5 and I6 (Figs. 4 and 6) having reduced portionsII, I8 and I9 (Figs. 4 and -7). The plate I3 is secured to the ends ofthe standards I4, I5 and I6 and the plate I2 is secured to the oppositeends of said standards at the point where the reduced por- -tions I'I,I8 and I9 begin, while the plate II is secured to the ends of saidreduced portions I'I, I8 and I9 (Fig. 4). This assembly is held in placeby means of a snap ring 20 (Figs. 4 and 5).

On the standard or spacing rod I4 is adjustably mounted apressure-responsive diaphragm 2I in any suitable manner as by means of apost 22 which extends through said rod I4 and is held therein by meansof a set screw 23, the operating axis of said diaphragm 2i being atright angles to the standard I4. The position of the diaphragm 2| withrespect to the standard I4 may be adjusted by means of set screw 23. Thediaphragm 2| is arranged for response to velocity pressures which areproportionalto the air speed of the craft on which the instrument isadapted. to be mounted and for this purpose the interior of saiddiaphragm 2I is arranged to be connected to the velocity pressureportion of a Pitot-static tube (not shown) by means of a conduit 24which terminates in a coupling member 25 which extends through the rearwall of the casing 9 and has a portion 26 exte'riorly of the casing anda portion 21a inside of the casing.

Motion of the diaphragm 2|, due to expansion and contraction thereof, istransmitted to a rock shaft 21 by means of a crank having one arm 28slidably engaging a U-shaped member ,29 on the diaphragm 2| and theother arm 36 being rigidly connected to the rock shaft 21 (Fig. 6). Therock shaft 21 is journaled in the plates l2 and I3 as shown in Fig. 4.Rigidly secured to the rock shaft 21 and at an angle there-to is a lever3| which is arranged to slidably engage a pin 32 carried by a gearsector 33 which is located on the opposite side of the plate l2, the pin32 projecting through an opening 34 provided in said plate |2.

The gear sector is carried by a shaft 35 (Fig. journaled in the platesII and I2 and is arranged to mesh with a pinion 36 carried on a hollowshaft 31 which projects through the plate II, the latter being providedwith a hub portion 38 for supporting said shaft 31. On the other end ofthe shaft 31 there is provided a gear 39 which meshes with another gear46 carried by a stub shaft 4| one end of which is journaled in an anglebracket 42 carried by a rotatable gear plate 43 and the other end ofwhich is journaled in said gear plate 43 (Fig. 5), said gear plate 43being journaled on a bushing 44 secured to fixed plate 45 which is heldstationary in the casing 9 by means of a threaded pin 46 (Fig. 4).Carried by and secured to the stub shaft 4| is a pinion 41 which mesheswith a gear 48 secured to a hollow shaft 49 which extends through thebushing 44 and on which is carried a pointer 56.

The pointer 56 cooperates with a scale 5| (Fig. 1) to indicate airspeed. The scale 5| is inscribed on a rotatable dial ring 52 (Figs. 4and 5) journaled on the fixed plate 45 and held on said fixed plate bymeans of a spacing ring 53 which also forms a bearing surface for saiddial ring 52. The front of the casing is closed by means of a coverglass 54 through which the pointer 56 and its cooperating scale 5| arevisible, the cover glass being held in place by means of a snap ring 55.The spacing ring 53 is prevented from rotating by means of a threadedpin 56 (Fig. 4). A hair spring 51 is provided for taking up the backlash in the gear train between pinion 36 and the gear 48, one end ofsaid hair spring being connected to the hollow shaft 31 and the otherend to a pin 58 carried by the fixed plate I I.

It will be seen that as the diaphragm 2| expands and contracts uponchanges in air speed its movement is transmitted to the rock shaft 21which in turn actuates the gear sector 33 and then the pointer 56through the gear train 36, 39, 46, 41 and 48. The gear sector 33 isprovided with a counterweight 59. The structure thus far describedconstitutes the air speed indicator portion of the instrument.

The rate-of-climb or vertical-speed indicating portion of the instrumentcomprises a. pressureresponsive diaphragm 66 (Figs. 4 and 6) which ismounted on a post 6| slidably extending through a tubular member 62secured to or formed integrally with a bracket 63 the ends of which aresecured to the standards or spacing rods l5 and I6 (Fig. 6). The insideof the diaphragm 66 is arranged for connection to a heat insulated tank(not shown) forming part of a standard rate of climb instrument by meansof a. conduit 64 which terminates in a coupling member 65 having aportion 66 outside of the casing and a portion 61 inside of the casing.At the point where conduit 64 terminates in the coupling device 65 thereis provided a capillary tube 68 through which the pressures inside andoutside of the diaphragm 66 tend to equalize in the usual manner when achange of altitude takes place, the free end of said capillaryterminating inside the casing 9 and the interior of said casing beingplaced in communication with static pressure by means 'of a connection16 to which the static pressure portion of a Pitot tube is usuallyconnected.

When an increase in altitude takes place, the diaphragm 66 expands untilthe change in altitude ceases whereupon the pressures on the inside andoutside of the diaphragm equalize through the capillary 68, the rate atwhich the equalization takes place being an indication of k the rate ofchange of altitude as is well known to those skilled in the art ofrate-of-climb instruments.

Movement of the diaphragm 66, due to its expansion and contraction, istransmitted to a rock shaft 1| which is also journaled in the plates I2and i3, the transmission being effected by means of a crank having onearm 12 slidably engaging a U-shaped member 13 secured to the center ofthe diaphragm 66 and having its other arm 14 rigidly connected to therock shaft 1|. A lever is secured to the rock shaft 1| at an anglethereto and is adapted to engage a pin 16 which projects through anopening 11 in the plate l2 and which is carried by a gear sector 18. Thegear sector 18 is provided with a counterweight 19 and is carried on astub shaft 86 journaled in the fixed plates II and I2 and is arranged tomesh with a pinion 8| carried by a shaft 82 one end of which isjournaled in the plate I2 and the other end of which extends through thehollow shafts 31 and 49. Secured to said end is a pointer 83 whichcooperates with a scale 94 inscribed on the fixed plate 45. A hairspring 85 is provided to take up the back lash betw sen the gear sector18 and pinion 8|, one end of said hair spring being connected to theshaft 82 and the other end 'to a pin 86 carried by the plate |2.

It will be seen from Figs. 4 and 5 that the pointers 56 and 83 arearranged about acommon pivot and in planes spaced one behind the other,and that shaft 49 extends through pointer 56 while shaft 82 extendsthrough pointer 56 and pointer 83.

Thus, it will be seen that as the diaphragm 66 expands and contracts dueto a rate of change in altitude or vertical speed, its movement istransmitted to the pointer 83 by means of the rock shaft 1|, lever 15,gear sector 18 and pinion 8|.

Means are now provided for adjusting the dial 52 and pointer 56 of theair speed indicator so' that for any desired normal cruising speed thepointer and the number representing the cruising speed on the scale 52are brought to a horizontal position, with the pointer pointing to 'theleft as viewed in Fig. 1, whereby said pointer moves upward when the airspeed decreases below the cruising speed, as in climbing, and movesdownward when the air speed increases, as in diving. In the form shownsaid means comprise a knob 81 accessible from the front of theinstrument (Figs. 1 and 4) and secured to a shaft 88 journaled in thecasing 9. Said shaft is arranged for abuts the wall of a recess providedin the lower.

portion of the casing and the other end of which abuts a collar 33secured to said shaft 33 (Fig. 4) On the shaft 33 is provided a pinion9! which is arranged to mesh with a pinion 92 (Fig. 3) carried on ashaft 93 which is parallel to the shaft 83 and is journaled in the lowerportion of the casing 9 in the same manner as the shaft 88, said pinion92 meshing in turn with the gear plate 43 on which is carried thebracket 42. Thus, rotation of the gear plate 43 causes the bracket 42 torevolve about the common axis of the pointers 39 and 83. As bracket 42revolves it carries with it the gear 49 which is caused to rotate due tothe planetary action between it and the gear 39 which at this time isrelatively stationary. Rotation of the gear 49 in this manner producesrotation of the pointer 39 through the gears 41 and 48 thereby producingthe required setting movement of the pointer. However, on the shaft 83there is provided another pinion 94 which is in engagement with the dialring 32 so that when the knob 81 is manipulated, the dial ring 32 iscaused to rotate simultaneously and synchronously with the pointer 39 sothat the number representing the desired cruising speed on the scale iiis brought to a horizontal position together with the pointer 39. Inorder to accurately determine the horizontal position to which thenumber of the scale is to be brought there is provided a fixed referencemarker 93 (Fig. 1).

It is to be understood that the gear ratios between gears 39 and 49,gears 41 and 48, gears 92 and 43, and gears 94 and 32 must be such thatfor one revolution of gear 43, the gear 32 (which carries the scale 3|)and pointer 39 will move in unison in equal angular amounts in the samedirection. For example, if the gear ratio of gear 38 to gear 49 is 3 :5and the ratio of gear 41 to gear 43 is also 3:5, then the ratio of gears92 and 43, and that of gears 94 and 32 must be such that the final ratiobetween gears 43 and 32 will be 16:25 as will now be explained. Usingthese ratios as examples, it will be seen from Fig. 8 that if gear 48makes one clockwise revolution about gear 39 which is stationary, gear49 will make of a revolution in a clockwise direction on its own axis.Then for one clockwise revolution of gear 49, gear 41 will likewise makeone clockwise revolution because they rotate together on the same shaft.Gear 43 being in mesh with gear 41, the former will make of a revolutioncounterclockwise for one clockwise revolution of gear 41 of for V of aclockwise revolution of gear 41, gear 48 will make x or of a revolutioncounterclockwise. But gear 43 has an additional rotation produced by thebodily rotation of gear 41 with its axis about the gear 43, and thatrotation of gear 43 is one revolution in a clockwise dimotion for oneclockwise revolution of the large gear 43 on which the gears 49 and 41are carried. Thus, the rotation of gear 48 is a differential rotationequal to one clockwise revolution and of a revolution counterclockwisefor one clockwise revolution of large gear 43, the net result being 1minus or 95 revolution of gear 43 clockwise for one clockwise revolutionof large gear 43. Hence, gear 43 and pointer 59 move in the samedirection as gear 43 and gear 32, namely, clockwise as viewed in Fig. 8or counterclockwise when viewed from the front of the instrument, andif, as previously stated, the -flnal ratio between gear 43 and gear 32is 16:25, then gear 32 will move 95 of a revolution in a clockwisedirection for one clockwise revolution of gear 43 "viewed in Fig. 8.Accordingly, when gear 43 makes one clockwise revolution, gear 43 andgear 32 both make of a revolution in a clockwise direction as viewed inFig. 8. Hence, pointer 39 carried by the shaft of gear 43, and scale'Iion gear 32 move in unison in equal increments in the same direction whenactuated by the knob 31.

By way of example, in Fig. 1 the scale 3! is shown in position toindicate a cruising speed of approximately 220 miles per hour and whenthe pointer 39 is in alignment with the reference,

marker 93 said pointer will be in a horizontal position therebyindicating level flight at said cruising speed of 220 miles per hour. Ifthe aircraft should depart from level flight as, for example, when itbegins to climb, the air speed will decrease and consequently thepointer 39 will move upward from the horizontal position. 011 the otherhand, if the craft goes into a dive the air speed will increase andconsequently the pointer 59 will move downward from its horizontalposition. By rotation of the dial ring 32 any number on the scale 3i maybe brought into coincidence with the reference marker 95, depending uponwhat cruising speed is to be maintained for level flight.

Means are also provided for adjusting the pointer 33 for its zeroposition so that for level flight it will be in a horizontal positionand pointing toward the right as viewed in Fig. 1. In the embodimentillustrated in the drawings said means comprise a pinion 96 also carriedon the shaft 88 for manipulation by the knob 31. Bald pinion is adapted,when the knob 81 is pushed inward of the casing, to mesh with a gear 91,carried on a shaft 98 which is journaled in a tubular member 99 securedto the supporting plate l2. On the end of said shaft 98 there isprovided a cam I99 which is adapted to engage the lower portion l9i ofthe post 8i so that upon rotation of said cam I99 by the knob 91 throughthe.

pinion 98 and gear 91 the diaphragm 89 is adapted to be raised orlowered with respect to its support 83 and along its operating axis,thereby causing actuation of the rock shaft H in a manner similar tothat when said rock shaft H is actuated by .expansion and contraction ofthe diaphragm 69. Then through the interconnecting transmissionmechanism between the rock shaft II and the pointer 83, the latter maybe adjusted to coincide with its zero position on the scale 89, saidzero position being at the right of the scale as shown in Fig. 1 and solocated that when the pointer 83 coincides therewith said pointer willbe in a horizontal position. Thus, it will be seen that the knob 81 andshaft 83 constitute a common means for bringing both pointers 59 and 83into a horizontal position as illustrated at 83' and 59, and when thepointer 59 is actuated the dial ring 52 is simultaneously andsynchronously rotated therewith in order to bring the numberrepresenting the desired cruising speed on the scale SI into ahorizontal position.

From the foregoing description, it will be seen that the diaphragms 2|and 39 are mounted in relatively fixed relation in the casing 9 insubstantially parallel planes and positioned so as to expand indirections towards each other. Also, the diaphragms are respectivelyconnected by means of cranks 39 and 14 to a pair of parallel rock shafts21 and II positioned at right angles to the operating axes of saiddiaphragms, the

two concentric pointers .50 and 59 being connected to the respectiverock shafts through gear sectors 98 and I9 and appropriate gear trainstherebetween. It will be further apparent that the rate-of-climb orvertical speed dial 5 is fixed while the .horizontal speed dial 52 isrotatable and the manually operable shaft 80 is movable axially to twopositions. In one position, namely, when the knob 91 is pulled outwardlyof the casing, the pinion 95 is out of mesh with gear 91 while pinion 9|is in mesh with gear 92, thereby causing gears 92 and 94 to rotate gearplates 43 and 52 to cause a simultaneous and synchronous setting of theair speed pointer 50 and its dial 52 while the diaphragm 2I remainsstationary with respect to the casing 9. In the second position of theshaft 88, namely, when the knob 81 is pushed inwardly of the casing, thepinion 9| is demeshed from gear 92 while pinion 96 is meshed with gear91 to cause operation of cam I to raise or lower diaphragm 60 andthereby cause a setting movement of the rate-of-climb pointer 83 withoutrotating diaphragm 60 or dial 45. The structure thus provided iscompact, simple but yet rugged and efficient.

On larger aircraft, particularly fighting craft such as bombing planes,there is usually a navigator or bomber in addition to the pilot, and thenavigator or bomber and pilot are in different cockpits. It is,therefore, desirable to provide means whereby the navigator or bombermay adjust the instrument embodying the present invention from hisposition which is remote from the instrument panel located n the cockpitof the pilot, so that if the navigator or bomber, for purposes of adesired maneuver, wishes to signal to the pilot a new cruising speed tobe maintained he may readily do so by manipulation of a control deviceaccessible to him. For this purpose the shaft 93 (Fig. 3) is providedwith an extension I02 projecting out of the lower compartment of thecasing 9. To this extension is connected a flexible shaft I03, thelatter being of sufficient length to reach from the instrument panel onwhich the instrument is mounted to the navigator orbombers cockpit. Theremote end of said flexible shaft I03 terminates in a crank handle I 04by means of which the shaft 93 at the instrument may be actuated tothereby operate the pinions 92 and 94 and gear plate 43 and dial ring52. At the remote end, the flexible shaft I03 is made to project througha casing I05 in which is located a worm gear a dial I01 which isprovided with an air speed scale I09. The worm gear I06 is actuated bymeans of a worm I09 provided on the flexible shaft I03. The scale I01 isvisible from the front of the casing I05 and cooperates with a fixedreference marker I10 to indicate the desired cruising speed for whichthe instrument at the pilot's instrument panel has been set.

There is thus provided a novel and compact aircraft speed indicatorwhich is adapted to indicate simultaneously the longitudinal orhorizontal speed of an aircraft and the vertical speed or rate of climbthereof. There are also provided novel means for adjusting the dial andpointer means of the horizontal or air speed indicating portion of theinstrument as well as the pointer of the vertical speed or rate of climbindicating portion of the instrument in order that both pointers may beadjusted to be in a horizontal position and in alignment for a conditionof level flight at a desired cruising speed, said pointers beingconcentrically mounted to form, in effect, a single I06 having securedthereto hinged indicator the arms of which are concentrically pivoted atthe center. of the face of the instrument whereby. when the. aircraftstarts climbing, right V and when the aircraft starts diving, theindicator will form an inverted V.' Further, novel means are alsoprovided for setting the instrument for a desired cruising speed from aremote point and for indicating the setting at the remote point.

Although only one embodiment of the invention has been illustrated anddescribed, various changes and modifications in the form and relativearrangement of parts, which will now appear to those skilled in the artmay be made without departing from the scope of the invention. Forexample, the novel mechanism for simultaneously and synchronouslysetting a dial and pointer without moving or disturbing the actuatingdevice may be applied to an independent air speed indicator or to anyindicating instrument such as an altimeter, tachometer or manifoldpressure gauge. Reference is, therefore, to be had to the appendedclaims for a definition of the limits of the invention.

What is claimed is:

1. In an aircraft speed indicating instrument, the combination of twoconcentrically pivoted pointers, means responsive to the horizontalspeed of an aircraft for actuating one of said pointers, meansresponsive to the vertical speed of said aircraft for actuating theother of said pointers, and means for setting said pointers so that theyform a horizontal line across the face of the instrument for levelflight at a desired horizontal cruising speed.

2. In an aircraft speed indicating instrument, the combination of twoconcentrically pivoted pointers, means responsive to the horizontalspeed of an aircraft for actuating one of said pointers, meansresponsive to the vertical speed of said aircraft for actuating theother of said pointers, and means including an axially shiftable shaftfor setting said pointers so that they form a horizontal line'across theface of the instrument for level flight at a desired horizontal cruisingspeed.

3. In an indicating instrument, the combination of a pair ofconcentrically pivoted pointers for respectively indicating two factorscontributing to the maintenance of a desired condition, means responsiveto one of said factorafor actuating one of said pointers, meansresponsive to the other factor for actuating the other of said pointers,and means for setting said pointers so that they form a straight linediametrically across the face of the instrument for any desired readingsof said pointers when the desired condition is maintained.

4. In an indicating instrument, the combination of two concentricallypivoted pointers for respectively indicating two factors contributing tothe maintenance of a desired condition, means responsive to one of saidfactors for actuating one of said pointers, meansresponsive to the otherfactor for actuating the other of said pointers, and means including anaxially shiftable shaft for setting said pointers so that they form astraight the hinged indicator will form an upline across the face of theinstrument for any dethe arms of said hinged indicator in one directionfor an increase in horizontal speed, means responsive to the verticalspeed of said aircraft for actuating the other arm of said hingedindicator in a direction opposite to that of the first arm for anincrease in downward vertical speed, and

means for setting said arms so that they form a horizontal linediametrically across the face of the instrument and point in oppositedirections for level flight at adesired horizontal cruising speed andform an upright V when the aircraft is climbing and an inverted V whenthe aircraft is diving.

6. In an aircraft indicating instrument, the combination of a hingedindicator having its hinged arms constituted by two concentricallypivoted pointers, means responsive to the horizontal speed of "anaircraft for actuating one of the arms of said hinged indicator in onedirection for an increase in horizontal speed, means responsive to thevertical speed of said aircraft for actuating the other arm of saidhinged indicator in a direction opposite to that of the first arm for anincrease in downward vertical speed, and means including an axiallyshiftable shaft for setting said arms so that they form a horizontalline across the face of the instrument and point in opposite directionsfor level flight at a desired horizontal cruising speed and form anupright V when the aircraft is climbing and an inverted V when theaircraft is diving.

7. In an indicating instrument, the combination of two concentricallypivoted pointers for respectively indicating two factors contributing tothe maintenance of a desired condition, means responsive to one of saidfactors for actuating one of said pointers, means responsive to theother factor for actuating the other of said pointers, and means forsetting said pointers so that they form a straight line across the faceof the instrument when the desired condition is maintained, saidlast-mentioned means including a manually operable shaft axially movableto two positions whereby in one position of said shaft one. of saidpointers is adjusted and in the other position of said shaft the otherpointer is adjusted.

8.- In an indicating instrument, the combination of twoconcentricallypivoted pointers for respectively indicating two factorscontributing to the maintenance of a desired condition, means responsiveto one of said factors for actuating one of said pointers, meansresponsive to the other factor for actuating v the other of saidpointers, means for setting said pointers so that they form a straightline diametrically across the face of the instrument when the desiredcondition is 'maintained, and means interconnected with saidlast-mentioned means for setting one of said pointers from a remotepoint.

9. In an indicating instrument, the combination of two concentricallypivoted pointers for respectively indicating two factors contributing tothe maintenance of a desired condition, means responsive to one of saidfactors for actuating one of said pointers, means responsive to theother factor for actuating the other of said pointers, means for settingsaid pointers so that they form a straight line diametrically across theface of the instrument when the desired condition is maintained, meansinterconnected with said lastmentioned means for setting one of saidpointers from a remote point, and means at said remote point forindicating the condition for which said last-mentioned pointer has beenset.

10. In an aircraft speed indicating instrument,

the combination of two concentrically pivoted pointers, means responsiveto the horizontal speed of an aircraft for actuating one of saidpointers, means responsive to the vertical speed of said aircraft foractuating the other of said pointers, means for setting said pointers sothat they form a horizontal line across the face of the instrument forlevel flight at a desired horizontal cruising speed, andmeansinterconnected with said last mentioned means for setting saidhorizontal speed pointer from a remote point.

11. In an aircraft speed indicating instrument, the combination of twoconcentrically pivoted pointers, means responsive to the horizontalspeed of an aircraft for actuating one of said pointers, meansresponsive to the vertical speed of said aircraft for actuating theother of said pointers, means for setting said pointers so that theyform a horizontal line across the face of the instrument for levelflight at a desired horizontal cruising speed, means interconnected withsaid lastmentioned means for setting said horizontal speed pointer froma remote point, and means at said remote point for indicating thecruising speed for which said horizontal speed pointer has been set..

12. In an aircraft indicating instrument, the combination of a casing, apair of pressureresponsive diaphragms mounted in said casing insubstantially parallel planes and positioned so as to expand indirections towards each other, one of said diaphragms being responsiveto rate of climb of an aircraft and the other being respon sive to hangsin horizontal air speed of said aircraft, a pair of parallel rock shaftsrespectively connected to said diaphragms and positioned at right anglesto the operating axes of said diaphragms, a pair of concentricallypivoted pointers, means respectively connecting said pointers to saidrock shafts for actuation thereby, a stationary dial for therate-of-climb pointer, a rotatable dial for the air speed pointer andarranged concentrically with said stationary dial, means for causing asetting movement of the rateof-climb pointer, means for causing aseparate setting movement of the air speed pointer, means for causing asetting movement of the rotatable dial simultaneously and synchronouslywith the setting movement of the air speed pointer, and manuallyoperable means for alternately actuating the setting means of therate-of-climb pointer and the setting means of the air speed.

pointer and rotatable dial.

13. In an aircraft indicating instrument, the combination of a casing, apair of pressureresponsive diaphragms mounted in said casing insubstantially parallel planes and positioned so as to expand indirections towards each other, one of said diaphragms being responsiveto rate of climb of an aircraft and the other being responsive to changein horizontal air speed of said aircraft, a pair of parallel rock shaftsrespectively connected to said diaphragms and positioned at right anglesto the operating axes of said diaphragms, a pair of concentricallypivoted pointers, means respectively connecting said pointers manuallyoperable means including an axially movable shaft for alternatelyactuating the set- I ,ting means of the rate-of-climb pointer and thesetting means of the air speed pointer and rotatable dial.

14. In an aircraft indicating instrument, the combination of a casing, apair of pressure-responsive diaphragms mounted in said casing innormally fixed relation thereto, one of said diaphragms being responsiveto rate of climb of an aircraft and the other being responsive to changein horizontal air speed of said aircraft, a pair of concentricallypivoted pointers, means respectively connecting said pointers to saiddiaphragms for actuation thereby, a relatively fixed dial for therate-of-climb indicating pointer, a relatively rotatable dial for saidair speed pointer and mounted in concentric relation with said fixeddial, means for causing a setting movement of said rate-of-climbpointer, and means for causing a setting movement of said air speedpointer while its actuating diaphragm remains relatively fixed and forcausing a simultaneous and synchronous setting movement of saidrotatable dial.

15. In an indicating instrument, the combination of a casing, a pair ofactuating devices mounted in said casing in normally fixed relationthereto, one of said devices being responsive to one factor and theother being responsive to a related factor contributing to themaintenance of a predetermined condition, a pair of concentric dials, apair of concentrically pivoted pointers cooperating with said dials torespectively indicate the two related factors, transmission mechanismsrespectively connecting said'pointers to said devices for actuation bythe latter, one of said dials being fixedly mounted in said casing andthe other being rotatably mounted therein, means for causing a separatesetting movement of the pointer which cooperates with the fixed dial,and means for causing a simultaneous and synchronous setting movement ofthe other pointer and the rotatable dial.

16. In an indicating instrument, the combination of a casing, a pair ofactuating devices mounted in said casing in normally fixed relationthereto, one of said devices being respons ve to one factor and theother being responsive to a related factor contributing to themaintenance of a predetermined condition, a pair of concentric dials, apair of concentrically pivoted pointers cooperating with said dials torespectively indicate the two related factors, transmssion mechanismsrespectively connecting said pointers to said devices for actuation bythe latter, one of said dials being fixedly mounted in said casing andthe other being rotatably mounted therein, means for causing a separatesetting movement of the pointer which cooperates with the fixed dial,means for causing a simultaneous and synchronous setting movement of theother pointer and the rotatable dial, and common means for alternatelyand at will actuating said two last-mentioned means from the exterior ofthe casing.

1'7. In an indicating instrument, the combination of a casing, a pair ofactuating devices mounted in said casing in normally fixed relationthereto, one of said devices being respons've to one factor and theother being responsive to a related factor contributing to themaintenance of a predetermined condition, a pair of concentric dials, apair of concentrically pivoted pointers cooperating with said dials torespectively indicate the two related factors, transmission mechanismsrespectively connecting said pointers to said devices for actuation bythe latter, one of said dials being fixedly mounted in said casing andthe other .being rotatably mounted therein, means for causing a separatesetting movement of the pointer which cooperates with the fixed dial,means for' causing a simultaneous and synchronous setting movement ofthe other pointer and the rotatable dial, and common means foralternately and at will actuating said two last-mentioned means from theexterior of the casing, said common means including a manually operableand axially movable rotatable shaft.

18. The combination in an aircraft indicating instrument including acasing adapted for mounting on an instrument board of an aircraft, anactutating device, a pointer, transmission means connecting said pointerto said device for actuation by the latter, and a dial cooperating withsaid pointer, of means fixedly mounting said actuating device in saidcasing, means rotatably mounting said dial in said casing, and gearmeans interconnecting said dial and pointer for causing simultaneous andsynchronous setting rotation thereof in unison relative to said casingand in equal amounts while said actuating device remains stationary insaid casing, whereby said pointer and dial may be rotated so as to bringthe pointer into the same predetermined position with respect to saidcasing for any desired reading of said pointer on said dial andrepresenting a predetermined condition of flight of the aircraft onwhich the instrument may be mounted, and movement of said pointerthereafter by said actuating device in either direction from saidposition indicates a departure from said predetermined condition offlight.

19. The combination in an' aircraft indicating instrument including acasing adapted for mounting on an instrument board of an aircraft, anactuating device, a pointer, transm=ssion means connecting said pointerto said actuating device for actuation by the latter, and a dialcooperating with said pointer, of means fixedly mounting said actuatingdevice in said casing, means rotatably mounting said dial in saidcasing, and means including a planetary gear train interconnecting saiddial and pointer for causing' simultaneous and synchronous settingrotation thereof in unison relative to said casing and in equal amountsin the same direction while said actuating device remains stationary insaid casing and without interfering with the actuation of said pointerby said actuating device, whereby said pointer and dial may be rotatedso as to bring the pointer into the same predetermined position withrespect to said casing.

for any desired reading of said pointer on said dial and representing apredetermined condition of flight of the aircraft on which theinstrument may be mounted, and movement of said pointer thereafter bysaid actuating device in either direction from said position indicates adeparture from said predetermined condition of flight.

20. The combination in an aircraft indicating instrument including acasing adapted for mounting on an instrument board of an aircraft, anactuating device, a pointer, transmission means connecting said pointerto said actuating device for actuation by the latter, and a dialcooperating with said pointer, of means fixedly mounting said actuatingdevice in said casing, means rotatably mounting said dial in saidcasing,

gear means interconnecting said dial and pointer for causingsimultaneous and synchronous setting rotation thereof in unison relativeto said casing and in equal amounts in the same direction while saidactuating device remains stationary in said casing and withoutinterfering with the actuation of said pointer by said actuating device,whereby said pointer and dial may be rotated so as to bring the pointerinto the same predetermined position with respect to said casing for anydesired reading of said pointer on said dial and representing apredetermined condition of flight to be maintained at said reading bythe aircraft on which the instrument may be mounted, and movement ofsaid pointer thereafter by saidactuating device ineither direction fromsaid position indicates a departure from said predetermined condition offlight, and means interconnected with said last-mentioned means forsetting said dial and pointer from a remote point.

21. The combination in an aircraft indicating instrument including acasing adapted for mounting on an aircraft, an actuating device, apointer, means connecting said pointer to said actuating device foractuation bythe latter, and a dial cooperating with said pointer, ofmeans fixedly mounting said actuating device in said casing, meansrotatably mounting said dial in said casing, gear means interconnectingsaid dial and pointer, for simultaneous and synchronous setting rotationthereof in unison relative to said casing and in equal amounts whilesaid actuating device remains stationary in said casing, and means foractuating said last-mentioned means, whereby said dial and pointer maybe settably rotated so as to bring the pointer into the samepredetermined position with respect to said casing for any desiredreading of said pointer on said dial and representing a predeterminedcondition of flight of the aircraft on which the instrument may bemounted, and movement of said pointer thereafter by said actuatingdevice in either direction from said position indicates a departure fromsaid predetermined condition of fli ht.

22. The combination in an aircraft indicating instrument including acasing adapted for mounting on an instrument board of an aircraft, apressure responsive device, a pointer, transmission means connectingsaid pointer to said pressure responsive device for actuation by thelatter, and a dial cooperating with said pointer, 01- meansfixedlymounting said pressure responsive device in said casing, means rotatablymounting said dial in said casing, and gear means interconnecting saiddial and pointer for causing simultaneous and synchronous settingrotation thereof in unison relative to said casing and in equal amountswhile said pressure responsive device remains stationary in said casingand without interfering with the actuation of said pointer by saidpressure responsive device, whereby said dial and pointer may besettably rotated so as to bring the pointer into .thesame predeterminedposition with respect to the casing for any desired reading ofsaid-iiointer on said dial and representing a predetermined condition offlight of the aircraft on which the instrument may be mounted, andmovement of said pointer thereafter by said pressure responsive devicein either direction from said position indicates a departure from saidpredetermined condition of flight.

23. The combination in an aircraft airspeed indicator including a casingadapted for mounting on aninstrumentboard of anaircraft, a pressureresponsive device having, means for connecting it to a .Pitot tubecarried by the aircraft and disposed to velocity pressures produced bythe flight of the aircraft whereby said device ex- '5 pands andcontracts in accordance with changes in airspeed of said aircraft, apointer, transmission means connecting said pointer to said pressureresponsive device for actuation by the latter in accordance with changesin airspeed, and a lo dial having an scale-cooperating with said pointerfor in cating airspeed, of means fixedly mounting said pressureresponsive device in said casing, means rotatably mounting said dial insaid casing, and gear means interconnect- 1; ing said dial and pointerfor causing simultaneous and synchronous setting rotation thereof inunison relative to said casing and in equal amounts in the samedirection while said pressure responsive device remains stationary insaid so casing, whereby said dial and pointer may be rotated into aposition in which the pointer is horizontal for any desired airspeedindicated by said pointer on said dial and represents level flight ofthe aircraft on which the indicator may as be mounted, and movement ofsaid pointer thereafter by said pressure responsive device upward ordownward represents a departure upward or downward, respectively, fromlevel flight.

24.. In an indicating instrument including a 30 casing, an actuatingdevice in said casing, a pointer, means connecting said pointer to saidactuating device for actuation by the latter, and a dial cooperatingwith said pointer, the combination of means fixedly mounting saidactuating device in said casing, means rotatably mounting said dial insaid casing, and means including a gear train interconnecting said dialand pointer for causing simultaneous and synchronous setting rotationthereof in unison relative to said casing o and in-equal amounts in'thesame direction, whereby said dial and pointer may be settably rotated soas to bring the pointer into the same predetermined position withrespect to the casing for any desired reading of said pointer on a saiddial.

25. In an indicating instrument including a casing, an actuating devicein said casing. a pointer, means connecting said pointer to saidactuating device for actuation by the latter, and so a dial cooperatingwith said pointer, of means fixedly mounting said actuating device insaid casing, means rotatably mounting said dial in said casing, andmeans including a planetary gear train interconnecting said dial andpointer for causing simultaneous and synchronous setting rotationthereof in unison relative to said casing. and in equal amounts in thesame direction and without interfering with the actuation of saidpointer by said actuating device, whereby said dial and pointer may berotated so as to bring the pointer into the same predetermined positionwith respect to the casing for any desired reading of said pointer onsaid dial.

26. An indicating unit having parts comprising a plurality of flightresponsive instrumentalities, a pointer for each of saidinstrumentalities arranged about a common pivot and in planes spaced onebehind the other, common shaft means extending through said pointers,means connecting each of said instrumentalities with its pointer wherebysaid pointers may be rotated about the axis of said shaft means, a dialfor each of said pointers, means for manually adjusting said pointersand dials to cause the pointers 1 to move into alignment withoutdisturbing the instrument readings in order to indicate desiredconditions during flight, and means for supporting said parts inoperative relation.

27. An indicating unit having parts comprising a plurality of flightindicating instruments, a pointer for each of said instruments arrangedin planes spaced one behind the other, common shaft means extendingthrough said pointers, means 9 connecting each of said instruments withits pointer whereby said pointers may be rotated about the axis of saidshaft means by the instrument connected thereto, means for manuallyadjusting said instruments and pointers whereby said pointers may beadjusted to cause the same to move into alignment in order to indicatedesired conditions during flight, and means for supporting said parts inoperative relation.

CARL J. CRANE.

FRANCIS G. NESBI'I'I.

